mirror of
https://github.com/silverstripe/silverstripe-framework
synced 2024-10-22 14:05:37 +02:00
72 lines
2.1 KiB
PHP
72 lines
2.1 KiB
PHP
<?php
|
|
/**
|
|
* Generates entropy values based on strongest available methods
|
|
* (mcrypt_create_iv(), openssl_random_pseudo_bytes(), /dev/urandom, COM.CAPICOM.Utilities.1, mt_rand()).
|
|
* Chosen method depends on operating system and PHP version.
|
|
*
|
|
* @package framework
|
|
* @subpackage security
|
|
* @author Ingo Schommer
|
|
*/
|
|
class RandomGenerator {
|
|
|
|
/**
|
|
* Note: Returned values are not guaranteed to be crypto-safe,
|
|
* depending on the used retrieval method.
|
|
*
|
|
* @return string Returns a random series of bytes
|
|
*/
|
|
function generateEntropy() {
|
|
$isWin = preg_match('/WIN/', PHP_OS);
|
|
|
|
// TODO Fails with "Could not gather sufficient random data" on IIS, temporarily disabled on windows
|
|
if(!$isWin) {
|
|
if(function_exists('mcrypt_create_iv')) {
|
|
$e = mcrypt_create_iv(64, MCRYPT_DEV_URANDOM);
|
|
if($e !== false) return $e;
|
|
}
|
|
}
|
|
|
|
// Fall back to SSL methods - may slow down execution by a few ms
|
|
if (function_exists('openssl_random_pseudo_bytes')) {
|
|
$e = openssl_random_pseudo_bytes(64, $strong);
|
|
// Only return if strong algorithm was used
|
|
if($strong) return $e;
|
|
}
|
|
|
|
// Read from the unix random number generator
|
|
if(!$isWin && !ini_get('open_basedir') && is_readable('/dev/urandom') && ($h = fopen('/dev/urandom', 'rb'))) {
|
|
$e = fread($h, 64);
|
|
fclose($h);
|
|
return $e;
|
|
}
|
|
|
|
// Warning: Both methods below are considered weak
|
|
|
|
// try to read from the windows RNG
|
|
if($isWin && class_exists('COM')) {
|
|
try {
|
|
$comObj = new COM('CAPICOM.Utilities.1');
|
|
|
|
if(is_callable(array($comObj,'GetRandom'))) {
|
|
return base64_decode($comObj->GetRandom(64, 0));
|
|
}
|
|
} catch (Exception $ex) {
|
|
}
|
|
}
|
|
|
|
// Fallback to good old mt_rand()
|
|
return uniqid(mt_rand(), true);
|
|
}
|
|
|
|
/**
|
|
* Generates a hash suitable for manual session identifiers, CSRF tokens, etc.
|
|
*
|
|
* @param String $algorithm Any identifier listed in hash_algos() (Default: whirlpool)
|
|
* If possible, choose a slow algorithm which complicates brute force attacks.
|
|
* @return String Returned length will depend on the used $algorithm
|
|
*/
|
|
function generateHash($algorithm = 'whirlpool') {
|
|
return hash($algorithm, $this->generateEntropy());
|
|
}
|
|
} |